1. From the Department of Neurology (M.D.G., D.T.), University of Miami Miller School of Medicine, Miami, Fla; the Department of Clinical Neurosciences (M.D.H.) and Foothills Medical Centre (M.D.H., K.R.), University of Calgary, Calgary, Alberta, Canada; the Division of Biostatistics and Epidemiology (Y.Y.P., R.H.M., B.D.W., S.D.Y.), Department of Medicine, Medical University of South Carolina, Charleston, SC; and NINDS Office of Clinical Research (C.S.M.), Bethesda, Md.